Instrument cluster testing

Some photos of the clusters In the marked photo,

12V is switched 12V from the ignition key feeding the input of the gauge VR

At the bottom right, "5V" is the trace feeding the 5V output of the VR over to the temp and oil gauges on that board trace

FS is to the fuel sender

TS is to the temp sender

OS is to the oil sender

RT is the green dash right turn indicator

So first hook a battery from 12V to cluster ground

Hook your test resistors to the sender terminals to ground, one at a time.

Depending on which test resistor you use should move the gauge. All three gauges should read the same on respective resistors, IE 23--25 ohms on each gauge should give you 1/2 scale. Allow a minute for the gauges to warm up and stabilize.

L = 73.7 Ohms (empty)
M = 23.0 Ohms (1/2)
H = 10.2 Ohms (full)


Another source shows as much as 78 ohms for empty, 21 for mid and 10 for full